Insulator



(No Model) T. BLANKINSOP 31 J. W. BROWN.

INSULATOR.

Patented June 16, 1896.

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ANDREW B GRAHAM PH 0 UNITED STATES PATENT OFFICE.

THOMAS BLANKINSOP AND JOSEPH V. BROXVN, OF MARTINS FERRY, OHIO.

INSULATOR.

SPECIFICATION forming part of Letters Patent No. 562,166, dated June 16, 1896.

Serial No. 584,720. (No model.)

To all whom it may concern:

Be it known that we, THOMAS BLANKINSOP and J osEPH W. BROWN,citiZens of the United States, residing at Martins Ferry, in the county of Belmont and State of Ohio, have invented a new and useful Improvement in Insulators, of which the following is a specification.

In producing a glass insulator having an attaching screw-stem it is important that the screw-stem should have its greatest strength at the shoulder of the screw which forms the joining line of the insulator with the wooden cross-arm or other part. For this purpose the insulator is molded upon a metal core which extends from the point of the screwstcm and crosses the shoulder into the head and thereby reinforces the insulator at the point where it resists the greatest strain of the wire.

Referring to the accompanying drawings, the joining of the screw-stem a with the head of the insulator is supplemented by a shoulder 1), which makes a joint with the cross-arm c, and to seal this joint the shoulder has an annular cutter or thread d, which, as the screw-stem is driven into a hole bored in the cross-arm, cuts or bites into the surface and seals the shoulder-joint, so that no water can reach the screw-hole in the arm. The head has an annular groove 6, within which the wireis secured, and above the groove the head terminates in an angular part f, adapted to receive a wrench whereby to drive the insulator screw-stem into the bore of the'arm.

A drip rim or jacket 9 is formed around the head from the base of the wire-engaging groove and depends over the shoulder like an inverted cup for the purpose of preventing the accumulation of ice around the base of the head and to strengthen it at the wire-engaging groove.

In applying the insulator a hole is bored in the cross-arm or other part and a screw-thread cut therein, into which the tapering stem of the insulator is screwed, so that the annular cutter of the shoulder will be embedded into the surface of the cross-arm outside of the screw-thread. The insulator can be used without other fastening for all-wire insulation and can be applied to any wooden part where a screw-threaded bore can be made.

In the drawings, Figure 1 shows the glass insulator with a metal reinforcing-plug, and Fig. 2 shows the insulator as applied to the wooden cross-arm.

Vhen the insulator is used within a building, the jacket may be dispensed with; but as an integral part of the insulator the jacketis of considerable advantage in forming a table or seat for the wire in applying it in the groove. As a band the jacket gives increased strength to the wire-bound part and serves as a hold for both hands in screwing down the insulator.

To claim- 1. A glass insulator for wires, having a head formed with a wire-engaging groove and a screw-stem joining the head by a shoulder and reinforced by an embedded metal plug or core extending above said shoulder into the head for the purpose stated.

2. A glass insulator for wires, having a screw-stem terminating in a shoulder formed with an annular cutter or thread on its j ointforming side, an annular groove above the shoulder supplemented by an annular part and a metallic plug or core embedded in the screw-stem and crossing the shoulder into the head for the purpose stated.

3. A glass insulator for wires,ha\'*ing a wireengaging groove,a screw-stem reinforced with an embedded metal plug or core anda rim or jacket depending over the stem from the base of the groove for the purpose stated.

4. A glass insulator for wires, having a screw-stem, terminating in a joint-forming shoulder and a head having a wire-engagin g groove and an annular rim or jacket depending from the base of said groove over said shoulder, for the purpose stated.

5. The herein-described glass insulator for wires formed with a screw-stem terminating in a shoulder having an annular cutter or thread on its under side, a metal plug or core embedded into said stem and crossing the shoulder into the head, an annular groove for the wire, an annular rim or jacket depending over the shoulder, and an angular part above the groove, for the purpose stated.

THOMAS BLANKINSOP. JOSEPH XV. BROYVN.

Witnesses:

SAMUEL F. DEAN, WILLIAM P. SNODGRASS. 

